I'm not finding where it was stated, but I recall that it was Nick Holland (who maintains a large portion of the official FAQ...) who said that needing to customize the root prompt shows an unnecessary dependence upon the root account. This can potentially lead to catastrophic mistakes (Everyone makes mistakes; just don't do them while logged in as root...) which would be circumvented by using sudo(8).

How do i enable this line for user? i added this line to .profile but it only works for root why not normal users? In normal user prompts it shows \e[0;36m[\h:\w]\n\$ \e[m instead of the colour one.
export PS1='\e[0;36m[\h:\w]\n\$ \e[m'

How do i enable this line for user? i added this line to .profile but it only works for root why not normal users? In normal user prompts it shows \e[0;36m[\h:\w]\n\$ \e[m instead of the colour one.
export PS1='\e[0;36m[\h:\w]\n\$ \e[m'

What does:
echo $TERM
give you as a non-root user?

If it isn't VT220 or similar it cannot interpret the DEC colour commands.